1. Field of the Invention
The present invention relates to a process cartridge and an image forming system or image forming apparatus (hereinafter referred to as an "image forming apparatus") on which such a process cartridge can be mounted. Such an image forming apparatus may be embodied, for example, as an electrophotographic copying machine, a laser beam printer, a facsimile device, a word processor or the like.
2. Related Background Art
In image forming apparatuses such as copying machines, a latent image is formed by selectively exposing an image bearing member uniformly charged, the latent image is then visualized with toner, and then the toner image is transferred onto a recording sheet, thereby forming an image on the recording sheet. In such image forming apparatus, whenever the toner is used up, new toner must be replenished. The toner replenishing operation not only is troublesome, but also often causes the contamination of the surroundings. Further, since the maintenance of various elements or members can be performed only by an expert in the art, most of the users feel inconvenienced by required maintenance.
In order to eliminate such drawbacks and inconvenience, an image forming apparatus wherein parts such as a developing device in which toner therein been used up or an image bearing member for which a service life thereof has expired can easily be exchanged, thereby facilitating the maintenance, by assembling the image bearing member, a charger, the developing device and a cleaning device integrally as a process cartridge which can be removably mounted within the image forming apparatus has been proposed and put into practical use, for example, as disclosed U.S. Pat. Nos. 3,985,436, 4,500,195, 4,540,268 and 4,627,701.
In an image forming apparatus utilizing the above-mentioned process cartridge, as a recording sheet feeding path from a photosensitive drum to a transfer station where an image is transferred from the photosensitive drum to a recording sheet, there is provided an adequate space permitting the feeding of the recording sheet in optimum direction for transferring the image at the transfer station.
However, in view of the compactness and the light-weightening of an image forming apparatus, it has been requested for reducing spaces for a recording sheet feeding area and a transferring area, as well as the compactness of a process cartridge. To this end, it is considered that the space for feeding the recording sheet is reduced. However, if such space is reduced, when a thicker recording sheet having the higher resilience such as a post card, visiting card or envelope is fed, since the thicker sheet is hard to be flexed, it is feared that convey guides are strongly rubbed with the thicker sheet to prevent the smooth feeding of the recording sheet, thus causing the poor feeding.
Incidentally, the inventors previously invented a process cartridge which could improve the positional accuracy of a transfer guide portion and improve the operability regarding the jam treatment by providing the transfer guide portion in the process cartridge, and filed as Patent Application (corresponding to the Japanese Patent Publication No. 61-48152, U.S. Pat. No. 4,609,276; refer to "member 10" therein).
The present invention relates to the improvement in such technique, and can cope with not only thin recording sheets, but also thicker recording sheets sufficiently.